1. Field of the Invention
This invention relates to methods of fabricating a stent from a blow molded tube.
2. Description of the State of the Art
This invention relates to the fabrication of a stent, from an expanded tube. Stents function to hold open and sometimes expand a segment of a blood vessel or other anatomical lumen such as urinary tracts and bile ducts. Stents are often used in the treatment of atherosclerotic stenosis in blood vessels. A “lumen” refers to a cavity of a tubular organ such as a blood vessel.
A stent has a cylindrical shape and includes a pattern with a number of interconnecting structural elements or struts. Some stents are designed so that they may be radially compressed (crimped) and radially expanded (to allow deployment). A stent can be fabricated from a tube that has been laser cut to form a stent pattern.
The stent must be able to satisfy a number of mechanical requirements. First, the stent must withstand structural loads, namely radial compressive forces, imposed on the stent as it supports the walls of a vessel. Therefore, a stent must possess adequate radial strength. Radial strength, which is the ability of a stent to resist radial compressive forces, is due to strength and rigidity around a circumferential direction of the stent. Radial strength and rigidity, therefore, may also be described as, hoop or circumferential strength and rigidity. Once expanded, the stent must adequately maintain its size and shape throughout its service life despite the various forces that may come to bear on it, including cyclic loading, which is induced by a beating heart.